


Be Still, My (Beating) Heart

by mznaughty01



Category: Teen Wolf (TV)
Genre: Alpha Derek Hale, Alpha/Beta/Omega Dynamics, Alternate Universe - Human, Alternate Universe - No Hale Fire, Background Relationships, Bottom Stiles Stilinski, Derek and Stiles are Mates, Half-Sibling Incest, Jealous Derek, Knotting, Lace Panties, M/M, Mating, Mating Cycles/In Heat, Mpreg, Omega Stiles Stilinski, One Shot, POV Derek Hale, Plot What Plot/Porn Without Plot, Possessive Behavior, Self-Lubrication, Size Difference, Underage Sex
Language: English
Status: Completed
Published: 2013-08-09
Updated: 2013-08-09
Packaged: 2017-12-22 21:03:00
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,787
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/917991
Author URL: https://archiveofourown.org/users/mznaughty01/pseuds/mznaughty01
Summary: <blockquote class="userstuff">
              <p>The time for games was definitely over. Because now? Now it was time for Derek to breed Stiles’s sweet ass.</p>
            </blockquote>





	Be Still, My (Beating) Heart

**Author's Note:**

> I read a panties kink story in another fandom by one of my favorite authors a few days ago and it made me want even more stories with panties kink, but done Sterek style. So I read some stories, then decided to write one of my own. Here is the result.
> 
> I was honestly tempted to name this story _One Trope, Many Kinks_. Because do we have A/B/O here? Yep. And the aforementioned panties kink? Check. Incest? Check. Jealous/possessive behavior? Check and check. Heat, knotting, self-lubing, mpreg...I think you guys are probably starting to get the picture, hahaha.
> 
> It's just, y'know, a really kinky story.

Funny enough, it wasn’t the out of place fabric which drew Derek’s attention. No, that honor belonged to the rectangular shaped slip of black which stood straight up in the air. The darkness of the tag made it very noticeable, surrounded by a sea of white as it was.

 _Frederick’s_ in cursive and _of Hollywood_ in print below, all of it in white. Except for the little maroon colored star that dotted the _i_ , the star several shades darker than the color of the underwear.

But they weren’t exactly underwear. At least not underwear in the sense of what Derek expected to find in the room he had lived in with Stiles every day since Mom had brought his red-faced, squalling, Omega half-brother home from the hospital sixteen years ago right up until the day Derek had left for college a couple years back.

They were...pink.

Lacy.

_Girlish._

Derek picked up the panties. Sexy as fuck tiny boyshorts, actually. There was just the one, that was all, in such a light pastel they had blended in almost seamlessly with the white cotton boxer briefs they had been laying on top of. Since he’d been five, and adamant about getting rid of his tighty whities because he’d wanted to be just like Derek and wear whatever Derek wore, Stiles had been sporting the same type of underwear as Derek.

And no matter how much he liked the looked of them, the feel of them, Derek had never in his life been tempted to wear women’s undergarments so it only stood to reason that Stiles wouldn't be tempted either.

So who the fuck did they belong to?

Not Laura, because most of her stuff was still at the apartment she shared with Derek twenty minutes away from SoCal’s main campus, hours to the south of Beacon Hills. They’d driven home just for a week’s visit, spring break. And Laura had only been in the house long enough to dump her bag on the floor just inside of the door to her and Cora’s room before she’d rushed right back out the house and had taken off in their Camaro. She hadn’t had time to unpack, much less to unpack _and_ to oversee the migration and invasion of her crap into Stiles’s underwear drawer, of all places.

Not Cora either. Because lace and Cora? Pink and Cora? _Girlish and Cora_? No, no and _no_.

Cora had taken after Mom, was an Omega just like her, and had been raised by Mom and her second husband, John Stilinski, a mild-mannered Beta. At her core, though, Cora was the same as Laura and Derek, who were both Alphas. She was a Hale, through and through. And the Hales were known throughout northern Cali to be some of the most aggressive of Alphas to have _ever_ been born. That was a cold, hard truth proven by their birth father and his brother each receiving life sentences under the Three Strikes Law when Cora had still been in diapers. Their third, and final, offenses had been the brutal, unprovoked beating of the Alpha who had made the simple mistake of expressing interest in the same Omega as Uncle Peter. The one year Derek and Cora had both been at Beacon Hills High together, Cora a freshman and Derek a Senior, Cora had threatened to use Derek’s fists to punch the faces and/or throats and/or junk of every Alpha that had looked at her for too long, regardless if lusty intent was involved or not.

Hand shaking, Derek forced himself to let go of the boyshorts without destroying them like he wanted, just putting them back where he’d gotten them from. Digging into his back pocket, teeth clenched tight, he retrieved his cell. Redial, then his phone was ringing Laura’s.

“What?” she snapped in greeting. “This better be good and you better make it _quick_.”

“Have you talked to Stiles?” Derek forced out after sucking in a calming gulp of air. He had questions that he knew Laura wouldn’t have the answers to as he was closer to Stiles than she would ever be. He was the one who talked to Stiles every other night compared to her irregular bi-weekly calls with him, but Derek still hoped that Laura maybe knew something, _anything_. Such as where Stiles was right at that very moment, why hadn’t he gotten home yet, had he been talking about any new Alphas lately, was that Alpha a female, did she like pink, was she maybe who he was spending his Saturday afternoon with, which didn’t actually matter, none of it, because all Derek really wanted to know was if she was _fucking Stiles_.

“Seriously? Are you for real right now?”

“Sound like I wasn’t?” Derek’s eyes never wavered from the taunting piece of lace. “Let me try this again, then—tell me when was the last time you fucking talked to Stiles and what the fuck was said.”

“No, Derek, I haven’t talked to that little shit and I have no plans to either, okay? Not until I get home tonight, much later tonight, that is if I come home at all.” A single beat, then, “Damn it, Lydia! You had better not let Jackson come before I—”

The line disconnected. No point in calling back as Laura was busy with two of Stiles’s classmates who just so happened to also be her two favorite Betas.

It had been during a night of hard partying the year before, on Derek’s twenty-first, with a cheap bottle of Wild Turkey being passed back and forth between them, along with a spliff, that Laura had drunkenly revealed her years’ long, ongoing, simultaneous relationships with Lydia Martin and Jackson Whittemore. The reason she liked them so much, despite having to keep them as her dirty secrets because they were eight years younger than her then twenty-three, was not because they both had pretty coverings on the outside, but because they were so, so fucking damaged by mommy and daddy issues on the inside. Their needs had hooked Laura as deeply as the easy attraction that naturally existed between Alphas and Omegas. She couldn’t ignore them, or their fucked up problems, once she was in the know. She’d tried, she had confessed, only to meet with failure each and every time.

As they finished out their last two years of high school, she would cater to their wants which were all expressed in misguided carnal desires, something she could, and very happily did, handle. Once they were legal, though, she would mate both of them, become their Alpha, and they would then be hers to care for and nurture, which she had every intention of doing. They were the whole of the reason she was pursuing her Masters in Psychology and planned to go for her Doctorates later.

_“Plus,” she’d told Derek, the features of her face relaxed, a lazy, fond smile tugging up the corners of her lips, “I can fuck them whenever and however I want with little risk of Lyds getting pregnant, and no worries at all with Jackson, since they’re both Betas. And Jackson will never fuck either of us without protection until we are all well and truly settled into our careers, so it’s just a good deal all around.”_

A familiar scent filled Derek’s nose. His eyes slid halfway shut as his mouth dropped open and he inhaled in a deep breath. He savored the addictive spicy-sweetness that coated his tongue, flowed down the back of his throat. He’d known it for most of his life, had missed it to an unbelievable degree just in the short time since he’d last been exposed to it during his visit home over Christmas break. He’d been soaking in it for the past couple hours as the aroma permeated all corners of the bedroom, at all times of day and night, whether the room was occupied or vacant, the main difference now being that it was suddenly so much more potent than it had been, even more so than it normally was.

Stiles was home. Derek hadn’t heard him come in, but Stiles _had_ to be somewhere in the house. Jesus Christ, his _smell_ , it was a tangible lusciousness.

Ignoring the reason he’d opened up Stiles’s underwear drawer to begin with, the basket at his feet full of boxer briefs that Derek had gathered up out of the center of the floor earlier and washed and had been getting ready to put away, he closed the dresser. Then made his way down the stairs to the living room where he found Stiles and Scott.

There was an intense need that couldn’t be ignored to seek Stiles out whenever he was anywhere near, which Derek never tried to fight, but especially wasn't at that very moment. Because who better to ask about the boyshorts, and where Derek could find their owner, than Stiles himself?

From the foot of the stairway, Derek watched Stiles, not yet making his presence known. The cause behind Stiles’s strong scent was clear. He was in heat, and not just starting it either, but partway through his first day. Beads of sweat slicked his neck and caused wet, errant tendrils to stick to his flushed skin. He’d grown his hair out since the last time Derek had seen him in person, but that was something Derek already knew from their frequent Skype sessions. Still, to see it now was to actually appreciate just how _good_ the longer length looked on Stiles.

Mouth hanging open, stuffed full of curly fries, Stiles laughed with his whole body at something Scott said. His expression was open and welcoming.

Scott was leaning in just a little too close, looking just a little too focused and much too interested, for Derek’s comfort. Scott was also an Alpha, so Stiles’s heat was drawing him in, the same way any Omega’s unrepressed heat did to an Alpha, Scott's friendship with Stiles of the past two to three years be damned.

Derek knew what was going on with Scott because he _understood_.

Stiles’s heat was doing the same to Derek, _despite Stiles being his sixteen year old little brother_. Doing the same to Derek as it had always done during those first few hours of every month growing up when it had hit sometime between midnight and two in the morning like clockwork. And every single time, Stiles had only gotten up out of his bed to take his suppressors when Derek had been reduced to croaking out a wrecked plea of, “Goddamn it, Stiles, _please_.”

Every. Single. Time.

Stiles had always been too much of a temptation. A regular goddamned tease whether he knew it or not, though Derek had often suspected that Stiles was very much aware of just what type of effect he had.

“ _Scott_ ,” Derek barked, intense satisfaction snaking through him when Scott scrambled away from Stiles.

“Dude, you’re home!” Stiles said after swallowing his mouthful of barely chewed food. He jumped to his feet and rounded the couch, throwing his arms around Derek soon as he was within touching distance and pressing in for a hug. “Thought you said you guys weren’t coming up ‘til tomorrow morning?”

“Change of plans.” Stiles’s head came up to just beneath Derek’s chin, so Derek was easily able to stare at Scott over the top of it. When Scott just gave a sheepish grin, Derek scowled.

Eyes widening comically, Scott stood up. “Hey, Stiles, I’m, uh, going to head home now. I’ll call you—”

Derek glowered.

“Or, actually, how ‘bout you call me—”

Derek glared.

“Hey, you know what, talking on the phone is completely overrated nowadays. Am I right or am I right?”

While Scott shoved his half eaten lunch back into the crinkled, greasy paper bag it had apparently come out of, Derek kept an eye on him. And even when he and Stiles were alone, Scott having just exited out the front door in a rush of tripped up feet, he still didn’t let go of Stiles, instead following his instincts to hold on tighter. “The _hell_ , Stiles? Why haven’t you taken your suppressors?”

“Okay, yeah, so, um, maybe I forgot?” Stiles replied, his answer muffled as his face was buried in the shirt covering Derek’s chest. His answer also sounded suspiciously question-like. “But I was with Scott, so it was cool.”

“You—”

“No, seriously, man, it was cool, Scott’s cool, I promise. Mom and Dad both like him. All day, he was a true gentleman, protected my virtue from imaginary villainous Alphas who were after the goods and everything. Y’know, you should really try to be nicer to him, make it a point to growl at him only, like, five times a day rather than your standard ten. It would do a lot of good, because right now he thinks you don’t like him.”

“I don’t like him.”

“You mean, you don’t know him. With you being gone at school all the time, you haven’t had much of a—”

“I don’t know him, but I _do_ know that I don’t like him.” 

“ _Be still, my heart_ ,” Stiles quipped, pulling back with a mischievous grin. “You scaring Alphas away has it all aflutter.”

Eyebrows quirked, Derek said, “Mountfort. He’s a bit obscure, surprised you even know the reference to be honest, but it’s actually _Be still, my beating heart_.”

“No, not Mountfort.” Stiles huffed in amusement, mouth twisted up at the corners. “The Postal Service and the lyrics are definitely _Be still, my heart_.”

“Christ.” Derek snorted. “Never change, Stiles, never change.”

“Only if you promise not to. We’re, like, a packaged deal, me and you. My milkshake brings all the Alphas to the yard and your Scowly-Glowering-Glare of Doom scares the shit out of them and sends them running. And that was Kelis that time, by the way, which you should totally know because—”

“Stiles?”

“Huh?”

“Shut up.”

“But _whhhy_? Your jealousy’s cute. Just saying.”

“ _Stiles_ —”

“Okay, fine, shutting up now.” Stiles slipped a hand into one of Derek’s, the fit perfect although Derek’s was twice as big. “C’mon, I have something to show you anyways.”

For the record? It wasn’t that Derek was jealous, okay. He was just...concerned. Yes, concerned, that was all. He wanted an Alpha for Stiles who would care for Stiles and love Stiles and take care of Stiles like Derek always had. Stiles deserved that and _so much more_.

Scott wasn’t good enough. Erica hadn’t been good enough. Matt sure the fuck hadn’t been good enough.

That right there was Stiles in a nutshell—Alpha bait since his first heat at the tender age of nine.

Derek let Stiles tug him up the stairs and into their bedroom. He sat down on the side of his own bed when Stiles pushed him towards it.

And it appeared that Derek wasn’t going to have to approach the subject of the boyshorts. Because Stiles had just made his way over to the dresser and pulled them out himself.

“Who-whose,” Derek began, trying to ask a question. But he stopped, fell silent, as Stiles pulled his t-shirt up and over his head, then dropped it down to the floor.

Flushed pink skin shiny with a light sheen of sweat and flecked with moles. Brown nipples that were already tight, pebbled hard. The defined, dark trail of hair that started at Stiles’s navel and traveled down into his—

Jeans he’d just unbuttoned, slid down his legs and kicked off along with the white boxer briefs he’d been wearing, leaving Stiles completely naked.

His cock was swollen, heavy with need, begging for attention and relief. It curved out from his body, same width as Derek’s, half as long.

Stiles stepped into the boyshorts. Pulled them up his legs until they sat low on his slender hips. The tip of his erection peeked out over the top, trapped against his lower belly, angry red to the pale pink of the lacy fabric.

Who knew that it would be a _thing_ seeing Stiles wearing less than Miss March in this year’s Sports Illustrated calendar that Derek had hanging on the wall of his room back at school? Who knew that it would be a _thing_ at all seeing Stiles wearing panties? Then again, truth be told, Stiles had always been a _thing_ for Derek, hadn’t he.

Throat clicking, Derek swallowed. Swallowed again. Then asked, “Whose are those?”

“Saw them last week while I was at the mall and, uh, well, I knew my heat was coming this weekend and knew you were coming this weekend, too.” Whispered, “And you always have liked those stupid swimsuit editions of Sports Illustrated too fucking much.” Stiles’s shoulders raised and lowered in a half shrug. “They’re mine.”

Or, in other words, Stiles had bought them to wear _for_ Derek.

No more denial, just the truth: this had been a long time in coming.

They were brothers for always. Forever.

But Derek refused to deny himself any further. To deny Stiles. Because to deny what Stiles was offering was impossible. And not because Stiles’s heat dictated Derek’s actions. His heat was unquestionably enticing, yes, but ultimately it did not control Derek or what Derek chose to do.

Derek refused to deny what Stiles was offering for one very simple reason. _He didn’t want to._

“C’mere,” he commanded, spreading his legs wide to make room for Stiles. Stiles immediately stepped forward and Derek curled his hands around the back of his thighs. He helped Stiles climb up onto his lap, got him settled just where he wanted, straddled across Derek with one bent knee to either side of Derek’s hips. Stiles was a slight yet solid weight that Derek bore with little effort and it was with his face nuzzled into the damp skin of Stiles’s neck that Derek muttered a hoarse, “Fuck.”

He slid a hand down Stiles’s back. Into the boyshorts. Pushed two fingers inside of Stiles, met no resistance, only readiness, Stiles’s natural slickness easing the way in. 

Removing his fingers, Derek asked, “Mom?”

“At the hospital visiting Ms. Miller. Won’t be home ‘til way later.”

“John?”

“Double shift.”

“Cora?”

“Krav Maga practice. Getting ready for a competition next week where she’s going up against some Omega she apparently has the hots for. Laura?”

“Busy. And not coming home anytime soon.”

“Oh, my God, we can so stop with twenty questions, then, right?”

The time for games was definitely over. Because now? Now it was time for Derek to breed Stiles’s sweet ass.

Stiles ground down on Derek as he hissed out a breathy, “Please say yes, _please_.”

“Yes.” Derek reached between their bodies and undid his fly. He stood up, holding Stiles high so as to give Stiles the needed room to push down Derek’s jeans and underwear just far enough to free Derek from constriction.

As Derek sank back down to the side of the bed, he slid inside of Stiles at the same time. The head of his cock easily pushed aside the elastic crotch that had been hidden up between Stiles’s cheeks for the most part.

Fingers pressed deep into the soft, tender flesh just beneath Stiles’s hips, Derek used his grip to ease Stiles up and down his cock. Slick leaked out of Stiles, bathing the uppermost parts of Derek’s thighs, and the portion of his jeans that were still in the way, with wet stickiness. The tiny bit of precome Stiles’s cock had produced smeared across the bottom of Derek’s shirt.

"Holy shit,” Derek growled, " _yes_."

Derek fucked Stiles just like that, slow and easy, gentle, until Stiles’s mouth dropped open in a silent _oh_ as his body seized up hard as he came. Omegas were meant to carry the babies made inside of them, not so much to make babies in others, so Stiles’s orgasm was standard fare for a male Omega, just a small trickle down the front of the boyshorts he had on.

With one last shove of his hips upwards, a yank of Stiles downwards, Derek came himself. His knot locked him into place. Hot, sensitive, pulsing. It pumped Stiles full of his come, his seed.

And when they finally separated thirty minutes later, they did so as mates, Stiles now a part of Derek just as much as Derek knew he was a part of Stiles.

And Stiles’s heat...

It was done, its purpose served.

Spread out on the bed behind a sleeping Stiles, curved around the smaller form in front of him, Derek splayed a palm over Stiles’s belly. His stomach was soft, flat. But it wouldn’t be either one for very much longer. A baby was in there. _Derek’s baby_.

When Mom and John got home, shit would be going down. Although, if they were being honest about the whole thing, neither would claim to be surprised. Because _nobody_ should’ve been surprised that this had happened. In fact, it said a lot about Derek’s willpower that he had managed to wait as long as he had to claim Stiles given just how much Stiles used to tempt him on those late nights every month. For fuck’s sake, Stiles’s first heat had come when he was only nine, when most Omegas were like Cora and didn’t go through it until they were thirteen at the earliest. Early heats only happened when an Omega was around a well-matched Alpha. Essentially, it meant that _for years_ Stiles’s body had been presenting itself as ready to Derek.

Ready to be mated. Ready to be fucked. Ready to be bred.

In a family of relationships that went against the societal norms of Alphas only mating with Omegas, and Betas only mating with other Betas, leave it to Derek and Stiles to manage to have the most accepted of relationships, with it still being the most taboo. While incestuous matings weren’t unheard of, they also weren’t commonly practiced outside of royalty who wanted to keep their bloodlines pure. Then there was also the major problem of matings under the age of eighteen being heavily frowned upon in the Western World. A special license would have to be obtained, else Derek would suffer the same fate as his father.

If anybody, _anybody_ , tried to separate Derek from Stiles...

Derek pressed a kiss to the back of Stiles’s neck. Their mixed scent calmed him, spoke in a soothing language to that most primal part of him that viewed _Stiles_ and _Mate_ and _Mine_ as all being interchangeable.

Yeah, there would most definitely be a massive fallout. But deal with it Derek would. Because Stiles, and their baby that Stiles carried inside of him, they were both worth it.

**Author's Note:**

> You can find me on [Tumblr](http://mznaughty01.tumblr.com/). I don't really use it much other than for occasional reblogging. I may start using it more in the future to ask for prompts when I want to write, but can't think of anything, who knows. But you can always stop by to say hi if you want.


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